1. Field of the Invention
This invention relates to a method for storing of an entity relationship diagram in a computer system, to a method for displaying of an entity relationship diagram on the display of a computer system and to a computer system for displaying of an entity relationship diagram.
2. Background and Prior Art
The point of departure of the present invention is the entity relationship model as described in ACM Transactions on Data Based Systems, Volume 1, No. 1, March 1976, Peter Pin-Shan Chen "The Entity-Relationship Model--Toward a Unified View of Data", pages 9-36. The entity-relationship model proposed by Chen is a data model. This model incorporates some of the important semantic information about the real world serving as a tool for data based design. The corresponding diagrammatic technique proposed by Chen is not optimal. This is because--especially in a complex diagram--a lot of redundancy is implemented, which has negative effects both on the intelligibility of the diagram and also on the number of memory locations necessary to store the diagram as well as the number of memory locations necessary to store data and access paths in a resulting relational database.
From U.S. Pat. No. 4,479,196 to Ferrer et al. a modified diagrammatic technique to represent an entity relationship model is known for usage in a data base system. This technique is directed to represent data bases in a form which is readily processed and efficiently utilized by digital computers. However the above stated drawbacks of the original technique proposed by Chen are not solved thereby.